3 minutes to understand laser welding

What is the difference between the “troika” in the laser processing field?

It is said that laser welding, laser cutting and laser marking together constitute the "troika" of laser processing technology, and it is widely used in the industrial field.

Compared with laser cutting and laser marking, laser welding has a relatively short development time and is more difficult than laser cutting and laser marking. Laser cutting and laser marking use lasers to destroy the surface structure or overall structure of a substance, while laser welding uses a laser to process and restructure a material structure. Material construction requires higher lasers and processing processes than simple material structure damage.

What is the difference between laser welding and traditional welding technology?

As a modern welding technology, laser welding has deep penetration, high speed, small deformation, low requirements on welding environment, high power density, no influence from magnetic field, not limited to conductive materials, and does not require vacuum working conditions. It does not produce X-rays and other advantages during the welding process, and is widely used in high-end precision manufacturing, especially in new energy vehicles and power battery industries.

However, compared with other welding processes, the cost of laser welding automation equipment is high; the welding precision equipment and the public construction joints have high requirements on equipment precision, and it is difficult to manually operate; the material properties and fixture accuracy of the materials to be welded are high.

The key to determining the quality of laser welding is laser energy control and welding technology.

(1) Laser energy control

Since the materials to be welded have different absorption rates for lasers of different wavelengths (ranging from 5% to 50%), the laser selection is different and the welding effect is completely different. In order to output a uniform and stable welding laser beam to the workpieces, it is necessary to have a good laser output power or to accurately control the laser output power. If the power is too low, the welding melt will be insufficient to affect the welding quality, and the power will be too high or fluctuate. It can cause undesirable effects such as splashes and stomata. Therefore, the control of laser energy has become one of the most critical technologies for laser welding.

(2) Welding technology

The laser and material interaction process is more complicated, laser welding effect and laser wavelength, power density, welding time, welding head angle, focus distance, laser absorption rate and cleaning degree of workpieces, thickness and thermal conductivityprotection. There are dozens of factors related to gas type and flow rate. Therefore, the laser weldingtechnology is also one of the key factors affecting the welding quality. It is necessary for the laser welding technicians to continually explore and summarize the long-term experimental accumulation to obtain a good welding effect.